Effects of substrate phonon absorption on the resonance behavior of metal-insulator-metal metamaterial terahertz absorbers

We have investigated effects of substrate phonon absorption on the resonance behavior of metal-insulator-metal double layer metamaterial absorbers in the terahertz frequency range. A sharp resonant absorption dip is clearly observed for a metamaterial-on-ground-plane structure fabricated on a GaAs substrate when THz radiation is incident from the surface metamaterials side. However, when the THz is incident from the substrate side to the ground-plane-on-metamaterial structures fabricated on a GaAs substrate, the resonance dip is almost merged into the broad background of acoustic phonon absorption. The resonant absorption is recovered when the GaAs substrate is replaced with a high-resistivity Si substrate.

Особенности локализации света неоднородной пленкой

The case is considered of light confinement within a thin inhomogeneous film of copper-doped amorphous carbon. The effect manifests itself due to light scattering by copper nanoparticles embedded in the film. The localization explains the increase of "two-phonon" absorption lines of infrared radiation by nanosized diamonds simultaneously existing in the film.